Bad Astronomy

MESSENGER images Venus

Last week, the Mercury probe MESSENGER passed by Venus, changing its orbit and preparing it for its series of rendezvouses (yeah, yeah, I know, three years of French I took) with the solar system’s smallest planet. The probe took some interesting images of Venus this time, too. I particularly liked this one:

These were taken as MESSENGER left Venus. I like them because first, they look like the views of Venus I get through my own Earthbound ‘scope (though right now Venus is only half full, and not a crescent). But also, I like them because of the sense of leaving, of moving on. It’s not an animation or anything, but it does convey the sense that MESSENGER is still on the go and has things to do.

Incidentally, the “480nm” in the image title means 480 nanometers. That’s the wavelength of light passed by the filter in the camera, and it’s roughly the blue-green part of the spectrum. It corresponds to one wavelength of light emitted by hydrogen (the “H-beta” line), though I’m not sure that matters here. It’s also is the wavelength of light where the Sun emits the strongest – some people assume it’s yellow, but it’s actually blue-green. The Sun doesn’t look that color because it emits yellow, orange, and red light too, and we see them blended together.

Anyway, next stop for MESSENGER: Mercury. Well, that’s misleading: it’ll pass by Mercury several times before getting into its parking orbit. The images from there will be very cool indeed.

Tip o’ the sunshield to Emily, of course.